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.error { color:#AA0000; }</style></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><div class="bloop_markdown"><p>Exactly, couldn’t say that any better. <code>guard</code> was part of this proposal in the first draft but was dropped due the same reasons Matthew just described.</p>
<p></p></div><div class="bloop_original_html"><style>body{font-family:Helvetica,Arial;font-size:13px}</style><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><br></div> <br> <div id="bloop_sign_1487346856661576960" class="bloop_sign"><div style="font-family:helvetica,arial;font-size:13px">-- <br>Adrian Zubarev<br>Sent with Airmail</div></div> <br><p class="airmail_on">Am 17. Februar 2017 um 15:46:33, Matthew Johnson (<a href="mailto:matthew@anandabits.com">matthew@anandabits.com</a>) schrieb:</p> <blockquote type="cite" class="clean_bq"><span><div><div></div><div>
<br>> On Feb 17, 2017, at 8:41 AM, Vladimir.S via swift-evolution <swift-evolution@swift.org> wrote:
<br>>
<br>> I think I like this, but what about guard?
<br>>
<br>> func f(x: Int) -> Int {
<br>> guard x > 0 else { return 0 }
<br>> ...
<br>> }
<br>>
<br>> vs
<br>>
<br>> func f(x: Int) -> Int {
<br>> guard x > 0 else { 0 }
<br>> …
<br>> }
<br>
<br>Any time you have a guard statement you no longer have a single expression. There is at least one expression in the guard clause itself, at least one in the else block, and at least one following the guard statement.
<br>
<br>>
<br>> ?
<br>>
<br>> On 17.02.2017 11:20, Adrian Zubarev via swift-evolution wrote:
<br>>> I’d like to revive an additive proposal that couldn’t make it into Swift 3.
<br>>> This proposal has a small improvement to the language compared to other big
<br>>> features currently being proposed. It almost feels like a bug fix rather
<br>>> than a new feature, but it still needs a full and quick review process.
<br>>>
<br>>> You can read the formatted version here:
<br>>> https://github.com/apple/swift-evolution/pull/608
<br>>>
<br>>>
<br>>> |return| consistency for single-expressions
<br>>>
<br>>> * Proposal: SE-NNNN
<br>>> <https://github.com/apple/swift-evolution/blob/master/proposals/nnnn-single-expression-optional-return.md>
<br>>> * Author: Adrian Zubarev <https://github.com/DevAndArtist>
<br>>> * Status: *Awaiting review*
<br>>> * Review manager: TBD
<br>>>
<br>>>
<br>>> Introduction
<br>>>
<br>>> Any single-expression closure can omit the |return| statement. This
<br>>> proposal aims to make this feature more consistent in some other corners of
<br>>> the language.
<br>>>
<br>>> Original swift-evolution thread: * [Pitch] [Stage–2] |return| consistency
<br>>> for single-expressions * [Pitch] (Bofore Swift 3) Make |return| optional in
<br>>> computed properties for a single case
<br>>> <https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20160523/019260.html>
<br>>>
<br>>>
<br>>> Motivation
<br>>>
<br>>> Closures can omit the |return| and have an inferred return type:
<br>>>
<br>>> |let _ = { 42 } // Type: () -> Int let _ = [1,2,3].map { $0 * 5 } // T == Int |
<br>>>
<br>>> There are also value returning code blocks in the language that feel the
<br>>> same but are inconsistent to the mentioned feature:
<br>>>
<br>>> |// Read-write computed property: var integer: Int { get { return 2016 } set
<br>>> { /* do some work */ } } // Read-only computed property: var string: String
<br>>> { return "hello swift" } // Function: func pi() -> Double { return 3.141 }
<br>>> // Read-Write subscript: subscript(index: Int) -> Int { get { return index
<br>>> % 2 } set { /* do some work */ } } // Read-only subscript: subscript(index:
<br>>> Int) -> Int { return index * 2 } |
<br>>>
<br>>>
<br>>> Proposed solution
<br>>>
<br>>> Make |return| optional for the following top level code blocks that only
<br>>> contain a single expression:
<br>>>
<br>>> * /variable-declaration/
<br>>> * /getter-setter-block/
<br>>> * /getter-clause/
<br>>> * /function-body/
<br>>> * /subscript-declaration/
<br>>>
<br>>> That will allow us to rewrite the above example to:
<br>>>
<br>>> |// Read-Write computed property: var integer: Int { get { 2016 } ... } //
<br>>> Read-only computed property: var string: String { "hello swift" } //
<br>>> Function: func pi() -> Double { 3.141 } // Read-Write subscript:
<br>>> subscript(index: Int) -> Int { get { index % 2 } ... } // Read-only
<br>>> subscript: subscript(index: Int) -> Int { index * 2 } |
<br>>>
<br>>> *Possible real world example:*
<br>>>
<br>>> |// Today public struct Character { public let source: Module.Source private
<br>>> let _pointer: UnsafePointer<Swift.Character> public var value:
<br>>> Swift.Character { return self._pointer.pointee } ... } // Rewritten: public
<br>>> struct Character { ... public var value: Swift.Character {
<br>>> self._pointer.pointee } ... } |
<br>>>
<br>>>
<br>>> Impact on existing code
<br>>>
<br>>> None, this change will only relax some existing rules.
<br>>>
<br>>>
<br>>> Alternatives considered
<br>>>
<br>>> Leave this as is and live with such inconsistency.
<br>>>
<br>>>
<br>>>
<br>>> --
<br>>> Adrian Zubarev
<br>>> Sent with Airmail
<br>>>
<br>>>
<br>>>
<br>>> _______________________________________________
<br>>> swift-evolution mailing list
<br>>> swift-evolution@swift.org
<br>>> https://lists.swift.org/mailman/listinfo/swift-evolution
<br>>>
<br>> _______________________________________________
<br>> swift-evolution mailing list
<br>> swift-evolution@swift.org
<br>> https://lists.swift.org/mailman/listinfo/swift-evolution
<br>
<br></div></div></span></blockquote></div><div class="bloop_markdown"><p></p></div></body></html>